docs: def initialize_base(self, es):
          """set parameters and state variable based on dimension,
          mueff and possibly further options.
  
          """
          ## meta_parameters.cs_exponent == 1.0
          b = 1.0
          ## meta_parameters.cs_multiplier == 1.0
          self.cs = 1.0 * (es.sp.mueff + 2)**b / (es.N**b + (es.sp.mueff + 3)**b)
          self.ps = np.zeros(es.N)
          self.is_initialized_base = True
          return self